Crown Boiler MWC Series, MWC116ENL, MWC116ELL, MWC116ENT manual Removing Combustion Chamber Cover

Figure 14.1: Removing Combustion Chamber Cover

WARNING

Soot deposits in the flue passages are a sign that the boiler may be operating at high carbon monoxide (CO) levels. After cleaning the boiler of soot deposits, check the CO level in the flue gas to insure that the boiler is operating properly.

If it is necessary to check CO, use a combustion analyzer, or other instrument which is designed to measure CO in flue gas (see Start-up section). A CO “sniffer” designed for testing CO levels in ambient air cannot be used to check boiler combustion.

A normal CO reading for an MWC series boiler is less than 50ppm (0.005%). A higher reading is indicative of a combustion problem.

Some causes of excessive CO include:

•Incorrectly sized or drilled burner orifice

•Partially plugged flue passages

•Improper manifold pressure

•Partial blockage of vent or intake system

•Foreign material in burner venturis or burner ports

•Disconnected regulator reference tube

•Damaged fan impeller or housing

•Damaged or missing inducer or flue gas gaskets

•Distorted or missing combustion chamber or flue collector components.

•Flue gas recirculation in damaged or improperly assembled concentric venting

e.Inspect the burner ports for debris. The burner can be cleaned with a soft brush. If the burner shows signs of deterioration, replace it.

f.Inspect the electrodes and flame rod for deposits. Clean as necessary.

g.Disconnect and remove the inducer from the boiler. The inducer is equipped with sealed ball bearings and does not require lubrication. Inspect the impeller and the pressure switch venturi (Figure 14.2) for dirt or debris. Clean as necessary with a soft brush.

h.Inspect the secondary (stainless steel) heat exchanger coil for debris. Clean as necessary by flushing with clean water. A soft nylon brush may be used in accessible areas. Drain and flush the inside of the heat exchanger and condensate collector as required. Do not use any cleaning agents or solvents.

i.Reinstall the inducer. If either of the inducer gaskets show signs of deterioration, replace them.

j.Inspect the vent system and terminal for obstructions and clean as necessary.

k.For direct vent appliances, proper reassembly and resealing of the vent-air intake system.

l.Inspect internal boiler piping for leaks and/or deteriorating gaskets. Repair as necessary.

m.Remove, inspect, and clean the condensate trap (Figure 14.3). Disconnect the wires from the trap. Use pliers to compress the spring clip on the drain hose (the hose leading from the secondary heat exchanger) and slide it upwards. Disconnect the drain hose from the trap. After removing the condensate trap from the boiler, disassemble the trap in a tray or pan, being careful to note the way in which the float ball and float ball retainer fit into the trap. Flush all parts of the trap with water and reassemble. Reinstall the trap on the boiler.

n.Reinstall the combustion chamber cover, inner cover, and all jacket panels and any wiring removed during the inspection/.cleaning process.

o.Perform the start-up and checkout procedure described in Section XII of this manual.

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